1. Field of the Invention
The present invention relates to a retardation plate and its manufacturing method, a circularly polarizing plate and ½ wave plate using same, and a reflective liquid crystal display which can be used in various fields such as personal computers, AV devices, portable information and telecommunications devices, games and simulation devices, and a vehicle-mounted navigation system.
2. Description of the Related Art
¼ wave plates whose retardation (Re) is ¼ of wavelength are used for various applications, such as reflective liquid crystal displays, optical disk pickups and anti-fogging films. On the other hand, ½ wave plates whose retardation (Re) is ½ of wavelength also have various uses such as in LCD projectors.
In these applications, it is desired that ¼ wave plates and ½ wave plates manifest their full function with respect to incident light in all visible wavelength regions. In this regard, examples of wide band retardation plates which can fully demonstrate their functions with respect to incident light in the visible wavelength region and formed by laminating two sheets of polymer film having mutually different optical anisotropy may be mentioned (e.g., Japanese Patent Application Laid-Open UP-A) No. 05-27118, JP-A No. 05-100114, JP-A No. 10-68816 and JP-A No. 10-90521).
However, in prior art laminated type retardation plates, two types of chips had to be formed by cutting a birefringence film stretched in one direction, in directions subtending mutually different angles with respect to the stretching direction, these chips then being stuck together by an adhesive material and laminated. Moreover, when the two chips were stuck together, the coating of the adhesive material, cutting and sticking led to cost increases while decreased performance due to angular offset when the chips were stuck together could not be disregarded, hence improvements were desired.